Neurologic attack and dynamic perfusion abnormality in neuronal intranuclear inclusion disease

Neuronal intranuclear inclusion disease (NIID) is a neurodegenerative disease characterized by eosinophilic hyaline intranuclear inclusions in cells in the central, peripheral, and autonomic nervous system and visceral organs. Although clinical diagnosis was difficult until recently, an increasing number of adult cases of leukoencephalopathy have been diagnosed antemortem with NIID based on the characteristic hyperintensity in the corticomedullary junction on diffusion-weighted imaging (DWI) and confirmatory skin biopsy.¹ While adult-onset NIID is characterized by slowly progressive dementia, it may also present with acute symptoms including stroke-like episodes and epileptic seizures.^1,2 However, pathophysiology of acute episodes remains largely unclear. Here we report a case of NIID with distinct neurologic deficits. Whereas chronic hypoperfusion on SPECT was reported in NIID,¹ we observed unexpected perfusion abnormalities using arterial spin labeling (ASL), which is a noninvasive, repeatable perfusion MRI method using magnetically labeled arterial blood water protons as endogenous tracer particles.³